Table 2.

CMR Data of Patients

Reperfusion Time
≤3 h24 h4 days7 days40 days
T2 transmural ischemic, ms80.8 (10.9)65.4 (5.5)80.5 (11.3)76.8 (12.1)65.4 (7.2)
T2 transmural remote, ms52.5 (6.7)57.2 (6.2)53.7 (6.2)58.3 (5.9)52.9 (8.3)
T2 infarct incl. hypointense core, ms80.5 (16.4)63.0 (9.0)81.5 (15.3)76.3 (16.6)65.2 (8.4)
T2 infarct excl. hypointense core, ms87.2 (15.1)65.2 (8.8)86.0 (16.6)81.3 (16.9)66.4 (7.0)
T2 salvaged, ms70.2 (9.7)64.4 (8.3)78.5 (14.9)68.9 (9.5)62.3 (8.2)
Myocardial area at risk, % of left ventricle39.9 (13.0)21.8 (12.2)42.8 (11.5)42.9 (13.0)20.1 (11.5)
Intramyocardial hemorrhage, % of left ventricle0.6 (0.5)1.1 (0.6)1.7 (1.4)1.7 (1.8)0.7 (0.6)
Infarct size, % of left ventricle30.3 (14.6)21.9 (11.9)
Microvascular obstruction, % of left ventricle2.7 (2.4)0.9 (0.8)
  • Data are presented as mean (SD). T2 maps were analyzed by placing regions of interests at the transmural ischemic, infarcted (with or without including areas suggestive of intramyocardial hemorrhage), salvage, and transmural remote areas in a midapical ventricular short-axis slice corresponding to the same anatomic level in all acquisitions to track T2 relaxation time changes over time. The different myocardial states were initially defined by the localization relative to late gadolinium enhancement.17 One patient died between day 4 and day 7 cardiac magnetic resonance, and 1 patient was unable to undergo late gadolinium enhancement imaging because of severe renal impairment; therefore, T2 information from the different myocardial states within the ischemic region was obtained from 14 of 16 patients.

  • T2 relaxation time was longer in the transmural ischemic myocardium than in the remote myocardium at all time points evaluated (≤3 hour, day 1, day 4, day 7, and day 40 after reperfusion). At the 24-hour time point, T2 values were 65.4±5.5 ms and 57.2±6.2 ms in the ischemic and remote myocardium, respectively (P<0.01). Similar results (even of greater magnitude) were shown when comparing T2 in the ischemic and remote myocardium at day 40 (65.4±7.2 ms versus 52.9±8.3 ms, P<0.01). However, T2 relaxation time in the ischemic myocardium showed significant variations across time: T2 at 24 hours was statistically shorter than at ≤3 hours (65.4±5.5 ms versus 80.8±10.9 ms, P<0.01), than at day 4 (65.4±5.5 ms versus 80.5±11.3 ms, P<0.01), and than at day 7 (65.4±5.5 ms versus 76.8±12.1 ms, P<0.01). In contrast, T2 in the ischemic myocardium at 24 hours did not differ from T2 at day 40 (65.4±5.5 ms versus 65.4±7.2 ms, P=0.99).

  • CMR indicates cardiac magnetic resonance.